Turbine blading



L THOM TURBINE BLADING Filed A 1922 INVENTOR TTOR N EY Patented Sept. 30, 1924.

UNITED STATES 1,510,113 PATENT OFFICE.

LOUIS N. THOMPSON, OF MOORE, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A. CORPORATION 01? PENNSYLVANIA.

TURBINE BLADING.

Application filed August 22, 1922.

To all whom it may 0071mm:

Be it known that I, Louis N. TnoMrsoN, a citizen of the United States, and a resident of Moore, in the county of Delaware and State of Pennsylvania, have invented a new and useful Improvement in Turbine Blading, of which the following is a specification.

My invention relates to turbine blading and it has for its object to provideshrouding therefor which shall be highly resistive to bending stresses and which shall not obstruct or interfere with the flow of motive fluid between, the turbine blades.

Apparatus embodying features of my invention is illustrated in the accompanying drawings, forming a part of this application, in which: Fig. 1 is a sectional view of a turbine showing blading having my improved shrouding applied thereto; ,Fig. 2 is a fragmentary perspective view of blading having my improved shrouding applied thereto; and Fig. 3 is a detail view showing the shrouding and means for securing it in place.

In the application of Eric Zetterquist, Serial No. 588,039, filed September, 18, 1922, and assigned. to the Westinghouse Electric & Manufacturing Company, there is disclosed and claimed turbine blading of the wide exhaust type in which motive fluid is received laterally and dischar ed peripherally, the blading being made in, sections which have triangular or wedge-shaped tips, the sides of the triangular or wedge-shaped tips adjacent to the motive fluid receiving side of the wide blade structure being shrouded and the other sides of the triangular or wedge-shaped tip portions being provided with suitable energy-abstracting elements, preferably of the curved or spoonoutline type, such as disclosed and claimed in the application of Alexander T. Kasley, Serial No. 486,517, filed July 21, 1921, and assigned to the TVestinghouse Electric and Manufacturing Company. Blading of this type is relatively tall so that long spans of the shrouding are included between the blades, and the shrouding is, therefore, sub jected to high bending stresses.

Accordingly, it is the object of my present intention to provide turbine blade shrouding which shall be highly resistive to centrifugal bending stresses. While my novel form of shroudmg is particularly use- Serial 'No. 583,580.

fnl in connection with turbine blading of the type disclosed in the aforesaid application of Zettcrquist, it will be understood that it may be used with other types of blading wherever its essential characteristics are desirable.

Referring now to the drawings for a more detailed description of my invention, I show turbine blades at 10 of the wide exhaust type which are made up of aplurality of sections 11 and 12 which have inclined tips 13 and 14;. The inclined tips 13 of the blade structure are provided with shrouding, hereinafter more particularly described, and the inclined tips 14 are provided with energy-abstracting portions 15 of the curved or spoon-outline type.

Each group of shrouding devised by me for the blade sections 12 comprises a plurality of adjoining sections having top and bottom portions which provide smooth outer and inner surfaces for the passage of steam, and the top and bottom portions are connected by transversely-disposed portions which add resistivity to deflection of the shrouding. The bottom portionsand the transverse portions are slotted to fit .between the turbine blades, and means are provided for securing the top portions to the tips of the blades and the inner portions to the sides of the bladesnso as to securely anchor the shrouding sections or strips with respect to the blades. v

For example, in the drawings, I show a plurality of adjoining Z-bar sections 16, each of which comprises top and bottom parallel portions 17 and 18' connected by a transverse portion 19 adding greatly to the strength of the section in resisting centrifugal bending stresses in a well-known manner. The upper portions 17 of the Z-bar sections 16 are perforated at QOtO receive tenons 21 which are. integral with the blade sections. The lower parallel portions 18 and the transverse connecting portions 19 are slotted, as shown in Fig. 3, so that a Z-bar strip may be assembled with the perforations 20 engaged about the tenons 21 and with the blade tips in the slots 22 of the lower parallel and the transverse connecting portions 18 and 19. Pins 28 are arranged in openings provided in the blade sections and engage in the corners between the portions 18 and 19 of the Z-bar in order to firmly hold the latter in place.

The first section of the shronding of each group facing the inlet side of the blades is of an obtuse angle form, that is, it comprises a top portion 25 which is perforated to receive the first row of tenons 21 and with a transverse portion 26 which extends inwardly at a suitable angle so as to contact and register with the lower parallel portion 18 of the adjacent Z-bar section 16.

\Vhen assembled, the upper portion 25 of the obtuse-angled section contacts with the upperportion 17 of the adjacent Z-bar section 16, and the upper portions 17 of the Z- bar sections are arranged successively in contact so as to provide a substantially continuous and smooth outer surface. In like mannor, the inwardly-extending or transverse portion 526 of the first obtuse-angled section and the inner portions 18 of the Z-bar sections 16 are arranged successively in contact so as to definea substantially smooth and continuous inner surface without interruptions or obstructions which would interfere with the How of steam.

It is apparent, therefore, that I have devised a shrouding construction for turbine blading which, for the same weight, is niuch stronger than that of the flat type heretofore proposed. Owing to the greater moment of inertia present with a section of the 2 type, sections of this type are much stronger and more resistive to centrifugal bending stresses. It will also be seen that I have provided shrouding sections of such a character and that I have arranged them in such a way as to provide inner and outer substantially continuous and smooth surfaces which permit of the flow of motive fluid without substantial interference.

IVhile I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1.. The combination with a row of turbine blades, of shrouding therefor comprising a plurality of adjoining sections each of which includes portions arranged parallel and transversely respectively to the blade tips so as to constitute shrouding which is highly resistive to bending stresses.

2. The combination with a row of turbine blades, of shrouding therefor comlprising adjoining sections, each of which has a top porlion litting against the blade lips and an inner transverse portion which is slotted to fit between the blades, and means cooperating with the top and transverse portions for securing them to the blades.

3. The combination with a row of turbine blades, of shrouding therefor which coniprises a plurality of sections secured to the blade tips and which have transvciscly extending portions to increase the resistivity of the sections to bending stresses.

l. The combination with a row of turbine blades. of shrouding therefor comprising a plurality of adjoining Z-shaped sections so cured to the blade tips.

5. The combination with a row of turbine blades, of shrouding therefor which coniprises a plurality of adjoining Z bar sections, each of which is provided with upper and lower parallel portions and :1 connecting transverse portion. the lower parallel and the transverse portions being slotted to fit between the blades, means for securing the upper parallel poitions to the blade tips, and means carried by the blades and cooperating with the inner parallel and transverse portions for holdin; the latter in position with respect to the. blades.

6. The combination with a row of turbine blades, of shrouding therefor which comprises a. plurality of adjoining Z-bar sections secured to the blade tips, the upper and lower parallel portions of the Z-bar sections respectively contacting to constitute substantially smooth surfaces.

7. In a turbine, the combination of a row of blades, sln'ouding for the blades which comprises a plurality of adjoining Z-bar sections having perforations to receive tenons on the blade tips and slits to receive the. blade tips, and pins carri nl by the blades and engaging with the lower corners of the Z-bar sections.

8. The con'ibination with a row of turbine blades, of shrouding therefor which co|uprises a plurality of adjoining Z-bar sec tions, the upper portion of each section being perforated to receive tenons on the blade tips and the transverse and lower portions thereof being slotted so as to lit between the blades, and holding means carried by the blades and cooperating with the lower corners of the Z-bar sections for holding the latter in position.

In testimony whereof, I have hereunto subscribed my name this 17th day of August, 1922. ii

LOUIS N. THOMPSON.

llll 

